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Updated: May 22, 2026

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Preparation and In Vitro Characterization of Dendrimer-based Contrast Agents for Magnetic Resonance Imaging
Published on: December 4, 2016
N'-Cyclo-dodecyl-idene-pyridine-4-carbohydrazide
Summary
This study details the crystal structure of a novel isoniazid derivative. The compound exhibits repeating chains stabilized by hydrogen bonds, with a cyclo-dodecyl ring in a square conformation.
Area of Science:
- Crystallography
- Medicinal Chemistry
- Organic Chemistry
Background:
- Isoniazid is a primary anti-tuberculosis drug.
- Structural modifications of isoniazid are explored to understand structure-activity relationships.
- The title compound is a novel derivative of isoniazid.
Purpose of the Study:
- To elucidate the crystal structure of the novel isoniazid derivative C(18)H(27)N(3)O.
- To analyze the intermolecular interactions and conformational aspects of the compound.
- To compare the structural features with the parent drug, isoniazid.
Main Methods:
- Single-crystal X-ray diffraction was employed to determine the crystal structure.
- Analysis of hydrogen bonding networks (N-H⋯O) was performed.
- Conformational analysis of the cyclo-dodecyl ring was conducted.
Main Results:
- The crystal structure reveals repeating C(4) chains along the b axis.
- N-H⋯O hydrogen bonds between amide functional groups, related by a b-glide plane, stabilize the structure.
- The cyclo-dodecyl ring adopts an approximate 'square' conformation, similar to cyclo-dodecane.
Conclusions:
- The crystal structure of the isoniazid derivative has been successfully determined.
- The hydrogen bonding and ring conformation provide insights into the molecular packing and stability.
- Structural similarities to parent compounds can inform future drug design.
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Removing one hydrogen from the intervening CH2 group with both...
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[4+2] Cycloaddition of Conjugated Dienes: Diels–Alder Reaction
The Diels–Alder reaction is an example of a thermal pericyclic reaction between a conjugated diene and an alkene or alkyne, commonly referred to as a dienophile. The reaction involves a concerted movement of six π electrons, four from the diene and two from the dienophile, forming an unsaturated six-membered ring. As a result, these reactions are classified as [4+2] cycloadditions.
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IUPAC names of carboxylic acids are systematically derived following a few rules discussed below.
For acyclic saturated monocarboxylic acids, the longest hydrocarbon chain containing the –COOH carbon is identified as the parent chain. Then, the last -e of the parent hydrocarbon name is replaced with a suffix -oic acid.
For acyclic saturated monocarboxylic acids, the longest hydrocarbon chain containing the –COOH carbon is identified as the parent chain. Then, the last -e of the parent hydrocarbon name is replaced with a suffix -oic acid.
Nomenclature of Carboxylic Acid Derivatives: Amides and Nitriles
Naming Amides
The IUPAC and common names of amides are derived from the parent carboxylic acid, by replacing the suffix “oic acid” and “ic acid,” respectively, with “amide.” In the following example, the IUPAC name ethanamide is derived from ethanoic acid, and the common name, acetamide, is obtained from acetic acid.
The IUPAC and common names of amides are derived from the parent carboxylic acid, by replacing the suffix “oic acid” and “ic acid,” respectively, with “amide.” In the following example, the IUPAC name ethanamide is derived from ethanoic acid, and the common name, acetamide, is obtained from acetic acid.

